Liberal Democrat business minister Ed Davey said a ten-year agreement with Royal Mail meant the signs were "extremely encouraging" for the future of the Post Office.
The agreement offers additional certainty to sub-postmasters and covers the full range of Royal Mail products available at post offices such as first and second class post, parcels, air mail, recorded and special deliveries.
Catherine Bearder, a Lib Dem Euro MP for the South East, said: "Post Offices are a vital part of our communities and are the lynchpin of our towns and villages.
"More than 20m people visit a Post Office every week to send letters to loved ones, to manage their finances or to renew passports for holidays and hundreds of thousands of pensioners rely on them every day for their pensions.
"Labour left Royal Mail in a terrible mess and it is Liberal Democrats in the Coalition Government who have stopped closures and put Royal Mail and the Post Office on a secure footing.
"The 20m people who use the Post Office every week don't deserve anything less from us."
Mr Davey added: "A year ago I set out a radical plan to transform Post Office's future, with £1.34bn of Government support and investment but without any closure programmes.
"Since then the Post Office has made good progress to become more competitive, building on its strengths.
"While it will take several years to turn round the Post Office's finances, it's increasingly clear the reforms are beginning to work.
"The 10-year deal struck between Royal Mail and the Post Office will give sub-postmasters and others greater confidence.
"The signs are extremely encouraging for the future of the Post Office."